But it's not an old tradition for most other folks. You didn't see a lot of this elsewhere. But Schindler's List brought the notion to people's attention, so now they know about it. And, being an easy thing to do (stones are always nearby), a lot more people have started doiing it. I see stones placed at the SAlem Witch memorials -- which aren't Jewish. I see them of random historic tombstones.

The Boston Holocaust Memorial went up two years after Schindler's List, so I have no "control" data. But, ever since it went up, I see stones there. And I suspect that not only Jewish people are leaving them there.